Photochromic spiropyrane derivative containing adamantyl group as well as preparation method and application of photochromic spiropyrane derivative
By introducing adamantyl ester groups onto spiropyran molecules, the problems of poor photochromic reaction and low lipid solubility of spiropyran materials in the solid state are solved, achieving efficient photoresponse and stable color-changing effect, which is suitable for solid-state functional devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI NORMAL UNIV
- Filing Date
- 2026-01-27
- Publication Date
- 2026-05-12
AI Technical Summary
Spiropyran materials have dense molecular packing in the solid state and lack free volume, which makes it difficult for photochromic reactions to occur. In addition, their poor lipid solubility affects their solubility and dispersion performance and photoresponse consistency in organic polymer matrices.
By introducing sterically hindered groups of adamantane esters onto spiropyran molecules and catalyzing esterification with 4-dimethylaminopyridine and dicyclohexylcarbodiimide, photochromic spiropyran derivatives containing adamantane groups are prepared, thereby improving their lipophilicity and steric hindrance and preventing tight packing.
The photochromic reaction of spiropyran in the solid state was realized, which improved the photoresponse efficiency and color-changing cycle stability, reduced the preparation difficulty and cost, and laid the foundation for its integrated application in solid-state functional devices.
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Figure CN122010965A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of organic synthesis technology, specifically relating to a photochromic spiropyran derivative containing an adamantyl group, its preparation method, and its application. Background Technology
[0002] Photochromic materials are a class of smart materials that undergo reversible molecular structure transformations under irradiation with a specific wavelength of light, resulting in significant color changes. Due to their unique photoresponse characteristics, they show broad application prospects in fields such as information storage, photoelectric switches, intelligent anti-counterfeiting, and environmental sensing. Spiropyran compounds, as classic organic photochromic small-molecule materials, have become one of the research hotspots in the field of photochromic materials due to their outstanding advantages such as simple synthesis processes, high color contrast, fast photoresponse speed, and excellent reversibility.
[0003] Despite their excellent intrinsic photochromic properties, spiropyran materials still face numerous technical bottlenecks in practical applications, particularly the urgent need to optimize their performance in solid form. Matrix-free solid spiropyran compounds, due to their dense molecular packing and lack of free volume, are difficult to undergo photochromic reactions, a core issue that significantly hinders the practical application of spiropyran materials.
[0004] Meanwhile, traditional spiropyran compounds also generally suffer from defects such as poor lipophilicity and easy oxidative degradation. Among them, the problem of poor lipophilicity will seriously affect its solubility and dispersion performance in organic polymer matrices, which will increase the difficulty of preparing solid block materials and make it difficult to form a uniform and stable solid system. Even if it is prepared, problems such as large differences in local color change effect and poor consistency of light response will occur due to uneven molecular distribution. Summary of the Invention
[0005] To address the aforementioned technical problems, this invention provides a photochromic spiropyran derivative containing an adamantyl group, its preparation method, and its application. The photochromic spiropyran derivative containing an adamantyl group exhibits good lipophilicity and solid-state photochromic properties.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0007] This invention provides a photochromic spiropyran derivative containing an adamantyl group, the structural formula of which is: , where n = 0 or 1, and R is H or OH.
[0008] The present invention also provides a method for preparing the aforementioned photochromic spiropyran derivative containing an adamantyl group, the method comprising the following steps:
[0009] 2-(3',3'-dimethyl-6-nitrospiro[chromene-2,2'-dihydroindole]-1'-yl)ethanol, adamantane carboxylic acid compounds, and 4-dimethylaminopyridine were dissolved in an organic solvent, cooled to -5 to 5 °C, and dicyclohexylcarbodiimide solution was slowly added dropwise under inert gas protection. The reaction was stirred for 1 to 1.5 h, then heated to room temperature, and the reaction was continued with stirring for 40 to 46 h. After post-treatment, photochromic spiropyran derivatives containing adamantane groups were obtained.
[0010] Furthermore, the adamantane carboxylic acid compound is one of 1-adamantane carboxylic acid, 1-adamantane acetic acid, and 3-hydroxy-1-adamantane acetic acid.
[0011] The molar ratio of the 2-(3',3'-dimethyl-6-nitrospiro[chromene-2,2'-dihydroindole]-1'-yl)ethanol to the adamantane carboxylic acid compound is 1:1.
[0012] The molar ratio of the adamantane carboxylic acid compound, 4-dimethylaminopyridine, and dicyclohexylcarbodiimide is 1:0.1~0.12:1~1.1.
[0013] The organic solvent is dichloromethane; the dicyclohexylcarbodiimide solution is obtained by dissolving dicyclohexylcarbodiimide in dichloromethane, and the concentration of the dicyclohexylcarbodiimide solution is 0.02~0.05 M.
[0014] The concentration of the adamantane carboxylic acid compound in the organic solvent is 0.01~0.05 M.
[0015] The post-processing method is as follows: the reaction solution is concentrated under reduced pressure, and then purified by column chromatography using a mixed solvent of petroleum ether and ethyl acetate as the eluent. The collected product is then concentrated and dried.
[0016] Furthermore, the volume ratio of petroleum ether to ethyl acetate is 3~5:1.
[0017] The present invention also provides the application of the aforementioned photochromic spiropyran derivative containing adamantyl groups as a solid photochromic material.
[0018] The photochromic spiropyran derivative containing adamantyl groups provided by this invention introduces sterically hindered groups of adamantyl ester series onto the spiropyran molecule, resulting in a relatively loose stacking mode of the compound, effectively preventing π-π stacking of spiropyran molecules and thus realizing the photochromic reaction of spiropyran in the solid state.
[0019] The method for preparing photochromic spiropyran derivatives containing adamantyl groups provided by this invention uses 4-dimethylaminopyridine and dicyclohexylcarbodiimide as catalysts to esterify 2-(3',3'-dimethyl-6-nitrospiro[chromene-2,2'-dihydroindole]-1'-yl)ethanol and adamantyl carboxylic acid compounds, introducing sterically hindered groups of adamantyl ester series onto the spiropyran molecule. This preparation method is simple, convenient for post-processing, and yields photochromic spiropyran derivatives containing adamantyl groups with high yield and good lipophilicity.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] 1. This invention prepares photochromic spiropyran derivatives containing adamantyl groups through an esterification reaction mediated by a catalytic system composed of 4-dimethylaminopyridine and dicyclohexylcarbodiimide. Dicyclohexylcarbodiimide acts as a dehydrating condensing agent, efficiently activating the carboxyl group of adamantyl carboxylic acid compounds, while 4-dimethylaminopyridine acts as an acylation catalyst, significantly accelerating the esterification process. The synergistic effect of these two agents enables the efficient esterification reaction of 2-(3',3'-dimethyl-6-nitrospiro[chromene-2,2'-dihydroindole]-1'-yl)ethanol with adamantyl carboxylic acid compounds. This preparation method requires no complex reaction apparatus, features mild and easily controllable reaction conditions, and simplifies post-processing, eliminating the need for cumbersome separation and purification steps, thus significantly reducing preparation costs and operational difficulty. Furthermore, the high yield of the target product provides strong support for large-scale production and demonstrates significant industrial application prospects.
[0022] 2. This invention precisely introduces adamantinate ester groups into spiropyran molecules via esterification. The hydrophobic structure of the adamantinate ester groups and their compatibility with organic solvents significantly improve the lipophilicity of the product, enabling the target derivative to dissolve rapidly and uniformly in various commonly used organic polymer matrices. This reduces the difficulty of preparing solid bulk photochromic materials and ensures the uniformity and stability of the prepared solid bulk system. It effectively solves key problems such as poor photoresponse consistency and unstable color-changing effect caused by uneven molecular dispersion in the preparation of traditional spiropyran solids, laying the foundation for its integrated application in solid-state functional devices.
[0023] 3. The adamantinate series of sterically hindered groups introduced onto spiropyran molecules through esterification reaction in this invention can effectively suppress the close packing of spiropyran molecules in the solid state through steric hindrance effect, providing sufficient space for photoisomerization process, thereby improving photoresponse efficiency and color-changing cycle stability. Attached Figure Description
[0024] Figure 1 The structural formula of the photochromic spiropyran derivative containing adamantyl groups provided by the present invention;
[0025] Figure 2 This is a synthetic route diagram of the photochromic spiropyran derivative containing adamantane carboxylate in Example 1;
[0026] Figure 3 The 1H NMR spectrum of the photochromic spiropyran derivative containing adamantane carboxylate in Example 1;
[0027] Figure 4 The mass spectrum of the photochromic spiropyran derivative containing adamantane carbamate in Example 1 is shown.
[0028] Figure 5 The UV-Vis spectra of the photochromic spiropyran derivative containing adamantane carboxylate in Example 1 are shown in the non-illuminated and illuminated spectra.
[0029] Figure 6 This is a synthetic route diagram of the photochromic spiropyran derivative containing adamantane acetate in Example 2;
[0030] Figure 7 The 1H NMR spectrum of the photochromic spiropyran derivative containing adamantane acetate in Example 2;
[0031] Figure 8 The carbon NMR spectrum of the photochromic spiropyran derivative containing adamantane acetate in Example 2;
[0032] Figure 9 The mass spectrum of the photochromic spiropyran derivative containing adamantane acetate in Example 2 is shown.
[0033] Figure 10 The UV-Vis spectra of the photochromic spiropyran derivative containing adamantane acetate in Example 2 are shown in the non-illuminated and illuminated spectra.
[0034] Figure 11 This is the synthetic route diagram for the photochromic spiropyran derivative containing 3-hydroxy-1-adamantane acetate in Example 3;
[0035] Figure 12 The 1H NMR spectrum of the photochromic spiropyran derivative containing 3-hydroxy-1-adamantane acetate in Example 3;
[0036] Figure 13 The carbon NMR spectrum of the photochromic spiropyran derivative containing 3-hydroxy-1-adamantane acetate in Example 3;
[0037] Figure 14 The mass spectrum of the photochromic spiropyran derivative containing 3-hydroxy-1-adamantane acetate in Example 3;
[0038] Figure 15The UV-Vis spectra of the photochromic spiropyran derivative containing 3-hydroxy-1-adamantane acetate in Example 3 are shown in the non-light and light-illuminated spectra.
[0039] Figure 16 The color change diagram of the solid product prepared from the photochromic spiropyran derivative containing adamantane carboxylate in Example 1 after non-light exposure and light exposure.
[0040] Figure 17 The solid product prepared from the photochromic spiropyran derivative containing adamantane acetate in Example 2 shows color changes under non-light and light exposure conditions.
[0041] Figure 18 The solid product prepared from the photochromic spiropyran derivative of 3-hydroxy-1-adamantane acetate in Example 3 shows the color change after exposure to light and without light. Detailed Implementation
[0042] The present invention will now be described in detail with reference to the embodiments.
[0043] Example 1
[0044] A photochromic spiropyran derivative containing adamantane carboxylate, the synthetic route of which is as follows: Figure 2 As shown, its preparation method includes the following steps:
[0045] 106 mg (0.5 mmol) of dicyclohexylcarbodiimide was dissolved in 10 mL of dichloromethane solution and then slowly added dropwise under a nitrogen atmosphere to 20 mL of dichloromethane solution containing 163 mg (0.5 mmol) of 2-(3',3'-dimethyl-6-nitrospiro[chromene-2,2'-dihydroindole]-1'-yl)ethanol, 84 mg (0.5 mmol) of 1-adamantanecarboxylic acid, and 7 mg (0.057 mmol) of 4-dimethylaminopyridine. The mixture was stirred at 0 °C for 1 h, then heated to room temperature and stirred for another 46 h. The solvent was then distilled under reduced pressure, and silica gel column chromatography was performed using a mixture of petroleum ether and ethyl acetate in a volume ratio of 4:1 as the eluent. The collected product was concentrated and dried to give 209 mg of a pale yellow solid, which was a photochromic spiropyran derivative containing adamantanecarboxylic acid ester, with a yield of 87.9%. It exhibits good solubility in dichloromethane, methanol, chloroform, and oleic acid solvents.
[0046] That 1H NMR (400 MHz, Chloroform-d) δ 8.48 (d, J = 2.7 Hz, 1H), 8.14 (dd, J = 8.9, 2.7 Hz, 1H), 7.20 (d, J = 9.0 Hz, 1H), 7.16 (d, J = 7.6 Hz, 1H), 7.08 (d, J = 7.3 Hz, 1H), 6.94 (dd, J = 14.9, 6.6 Hz, 2H), 6.78 (d, J =7.8 Hz, 1H), 6.44 (d, J = 15.9 Hz, 1H), 3.79 – 3.57 (m, 4H), 1.82 – 1.66 (m,15H), 1.45 (s, 3H), 1.16 (s, 3H). For example... Figure 3 As shown.
[0047] Its mass spectrum is as follows Figure 4 As shown.
[0048] The UV images of the chloroform solution containing the photochromic spiropyran derivative of adamantane carboxylate prepared in this embodiment under non-light illumination, 365nm wavelength UV light for 1 min, and 405nm wavelength UV light for 1 min are shown below. Figure 5 As shown in the figure, after 1 minute of 365nm ultraviolet light irradiation, there is a distinct cyanine peak at around 600nm, indicating that 365nm ultraviolet light irradiation causes some closed-ring spiropyrans to convert to open-ring cyanine.
[0049] Example 2
[0050] A method for preparing a photochromic spiropyran derivative containing adamantane acetate, the synthetic route of which is as follows: Figure 6 As shown, its preparation method includes the following steps:
[0051] 624 mg (3.0 mmol) of dicyclohexylcarbodiimide was dissolved in 60 mL of dichloromethane solution and then slowly added dropwise under a nitrogen atmosphere to 120 mL of dichloromethane solution containing 973 mg (2.8 mmol) of 2-(3',3'-dimethyl-6-nitrospiro[chromene-2,2'-dihydroindole]-1'-yl)ethanol, 537 mg (2.8 mmol) of 1-adamantaneacetic acid and 37 mg (0.3 mmol) of 4-dimethylaminopyridine. The mixture was stirred at 0 °C for 1 h, then heated to room temperature and stirred for another 46 h. The solvent was then distilled under reduced pressure, and silica gel column chromatography was performed using a mixture of petroleum ether and ethyl acetate in a volume ratio of 3:1 as the eluent. The collected product was concentrated and dried to give 598 mg of a pale yellow solid, which was a photochromic spiropyran derivative containing aadamantaneacetic acid ester, with a yield of 41%. It exhibits good solubility in dichloromethane, methanol, chloroform, and oleic acid solvents.
[0052] That 1 H NMR (400 MHz, Chloroform-d) δ 8.06 – 7.98 (m, 2H), 7.20 (t, J =7.7 Hz, 1H), 7.08 (d, J = 7.3 Hz, 1H), 6.94 – 6.87 (m, 2H), 6.75 (d, J = 8.7Hz, 1H), 6.69 (d, J = 7.8 Hz, 1H), 5.90 (d, J = 10.4 Hz, 1H), 4.19 (m, 2H), 3.55 – 3.35 (m, 2H), 2.01 (s, 2H), 1.92 (s, 3H), 1.71 – 1.58 (m, 6H), 1.55(6H), 1.28 (s, 3H), 1.16 (s, 3H). For example... Figure 7 As shown.
[0053] That 13C NMR (400 MHz, Chloroform-d) δ 179.12, 175.19, 153.21, 150.50,145.79, 139.58, 131.76, 127.84, 124.40, 123.90, 123.61, 122.51, 122.30,121.95, 112.11, 109.74, 63.81, 55.89, 50.36, 48.21, 45.11, 41.56, 39.45,36.66, 32.87, 31.43, 28.66, 26.39, 25.65, 25.60, 24.88, 20.52. (For example...) Figure 8 As shown.
[0054] Its mass spectrum is as follows Figure 9 As shown.
[0055] The UV images of the chloroform solution containing adamantane acetate photochromic spiropyran derivative prepared in this embodiment under non-light illumination, 365 nm wavelength UV light for 1 min, and 405 nm wavelength UV light for 1 min are shown below. Figure 10 As shown in the figure, after 1 minute of 365nm ultraviolet light irradiation, there is a distinct cyanine peak around 600nm, indicating that 365nm ultraviolet light irradiation causes some closed-ring spiropyrans to convert to open-ring cyanine. After 1 minute of 405nm ultraviolet light irradiation, there is also a cyanine peak around 600nm, indicating that 405nm ultraviolet light irradiation causes some closed-ring spiropyrans to convert to open-ring cyanine. However, spiropyrans have a stronger response to 365nm ultraviolet light.
[0056] Example 3
[0057] A method for preparing a photochromic spiropyran derivative containing 3-hydroxy-1-adamantane acetate, the synthetic route of which is as follows: Figure 11 As shown, its preparation method includes the following steps:
[0058] 131 mg (0.6 mmol) of dicyclohexylcarbodiimide was dissolved in 12 mL of dichloromethane solution and then slowly added dropwise under a nitrogen atmosphere to 25 mL of dichloromethane solution containing 203 mg (0.6 mmol) of 2-(3',3'-dimethyl-6-nitrospiro[chromene-2,2'-dihydroindole]-1'-yl)ethanol, 121 mg (0.6 mmol) of 3-hydroxy-1-adamantaneacetic acid and 8 mg (0.065 mmol) of 4-dimethylaminopyridine. The reaction was stirred at 0 °C for 1 h, then heated to room temperature and stirred for another 46 h. The solvent was then distilled under reduced pressure, and silica gel column chromatography was performed using a mixture of petroleum ether and ethyl acetate in a volume ratio of 3:1 as the eluent. The collected product was concentrated and dried to give 197 mg of a pale yellow solid, which was a photochromic spiropyran derivative containing 3-hydroxy-1-adamantaneacetic acid ester, with a yield of 62.9%. It exhibits good solubility in dichloromethane, methanol, chloroform, and oleic acid solvents.
[0059] That 1 H NMR (400 MHz, Chloroform-d) δ 8.06 – 7.95 (m, 2H), 7.20 (t, J =7.7 Hz, 1H), 7.08 (d, J = 7.0 Hz, 1H), 6.96 – 6.84 (m, 2H), 6.75 (d, J = 8.7Hz, 1H), 6.69 (d, J = 7.8 Hz, 1H), 5.90 (d, J = 10.4 Hz, 1H), 4.20 (m, 2H), 3.43 (m, 2H), 2.10 (s, 2H), 1.94 (s, 3H), 1.69 (m, 6H), 1.49 (s, 3H), 1.46 (s, 3H), 1.16 (s, 3H), 0.88 (s, 3H). For example... Figure 12 As shown.
[0060] Its 13C NMR (400 MHz, Chloroform-d) δ 171.69, 159.57, 146.82, 141.20, 135.80, 128.38, 127.96, 126.09, 122.88, 122.03, 121.91, 120.02, 118.60, 115.69, 107.01, 106.64, 62.17, 52.96, 48.97, 42.59, 42.52 (3C), 36.78 (3C), 32.85, 28.68 (3C), 25.96, 20.00. (The last sentence appears to be incomplete and possibly refers to a different 13C NMR spectrum.) Figure 13 As shown.
[0061] Its mass spectrum is as follows Figure 14 As shown.
[0062] The chloroform solutions containing the photochromic spiropyran derivative of 3-hydroxy-1-adamantane acetate prepared in this embodiment are shown in the following images: [Images of chloroform solutions under non-light, 365nm UV light for 1 min, and 405nm UV light for 1 min]. Figure 15 As shown in the figure, after irradiation with 365nm UV light for 1 minute, a characteristic absorption peak of the cyanine structure appears around 600nm, indicating that 365nm UV light transforms the closed-ring spiropyran structure into an open-ring cyanine structure. The same solution, irradiated with 405nm light for 1 minute, also shows a cyanine absorption peak around 600nm, but it is very weak, indicating that this adamantane-spiropyran derivative responds faster to 365nm UV light than to 405nm light.
[0063] Application Example 1
[0064] Application of the photochromic spiropyran derivative containing adamantane carboxylate prepared in Example 1 as a solid-state photochromic material
[0065] After mixing 1g of Dow Corning 184 silicone rubber base material with 0.1g of Dow Corning 184 silicone rubber curing agent, 150uL of dichloromethane solution containing 1mg of the photochromic spiropyran derivative containing adamantane carboxylate prepared in Example 1 was added. The mixture was then subjected to rotary evaporation under reduced pressure at 35°C for 30min, vacuumed at room temperature in a vacuum drying oven for 30min, and then heated in a 70°C oven for 1.5h to obtain a solid product.
[0066] After irradiating the solid-state product with 365nm ultraviolet light for 3 seconds, the product changed from pale yellow to purple. After placing it in a 50°C oven for 3 minutes, the product changed from purple back to its original pale yellow color. Figure 16 As shown, the photochromic spiropyran derivative containing adamantane carboxylate prepared in Example 1 exhibits high photoresponse efficiency and good color-changing cycle stability.
[0067] Application Example 2
[0068] Application of the photochromic spiropyran derivative containing adamantane acetate prepared in Example 2 as a solid-state photochromic material
[0069] After mixing 1g of Dow Corning 184 silicone rubber base material with 0.1g of Dow Corning 184 silicone rubber curing agent, 100uL of acetone solution containing 1mg of the photochromic spiropyran derivative containing adamantane acetate prepared in Example 2 was added. The mixture was then subjected to rotary evaporation under reduced pressure at 35°C for 30min, vacuumed at room temperature in a vacuum drying oven for 30min, and then heated in a 70°C oven for 1.5h to obtain a solid product.
[0070] After irradiating the solid product with 365nm ultraviolet light for 3 seconds, the product changed from light pink to dark purple. After placing it in a 50°C oven for 3 minutes, the product changed from dark purple back to its original light pink. Figure 17 As shown, the photochromic spiropyran derivative containing adamantane acetate prepared in Example 2 exhibits high photoresponse efficiency and good color-changing cycle stability.
[0071] Application Example 3
[0072] Application of the photochromic spiropyran derivative containing 3-hydroxy-1-adamantane acetate prepared in Example 3 as a solid-state photochromic material
[0073] After mixing 1g of Dow Corning 184 silicone rubber base material with 0.1g of Dow Corning 184 silicone rubber curing agent, 250uL of dichloromethane solution containing 1mg of the photochromic spiropyran derivative containing 3-hydroxy-1-adamantane acetate prepared in Example 3 was added. The mixture was then rotary evaporated under reduced pressure at 35°C for 30min, vacuumed at room temperature in a vacuum drying oven for 30min, and then heated in a 70°C oven for 1.5h to obtain a solid product.
[0074] After irradiating the solid product with 365nm ultraviolet light for 3 seconds, the product changed from light pink to dark purple. After placing it in a 50°C oven for 8 minutes, the product changed from dark purple back to its original light pink. Figure 18 As shown, the photochromic spiropyran derivative containing 3-hydroxy-1-adamantane acetate prepared in Example 3 exhibits high photoresponse efficiency and good color-changing cycle stability.
[0075] In Application Examples 1-3, the color of the solid product changes before and after light exposure because, under light conditions, the spiropyran molecule transforms from a twisted, non-conjugated spirocyclic structure into a planar, highly conjugated π-cyano structure. This large π-conjugated system can absorb visible light, thus producing color. The absorption peak is usually around 550-600 nm, appearing as a bluish-purple color. This color-changing property allows it to be applied in fields such as intelligent anti-counterfeiting, information encryption, intelligent sensing, and photosensitive lenses.
[0076] The above-described detailed description of a photochromic spiropyran derivative containing an adamantyl group, its preparation method, and its application is illustrative rather than limiting. Several embodiments may be listed within the defined scope. Therefore, variations and modifications without departing from the overall concept of the present invention should be within the protection scope of the present invention.
Claims
1. A photochromic spiropyran derivative containing an adamantyl group, characterized in that, The structural formula of the photochromic spiropyran derivative containing adamantyl groups is: , where n = 0 or 1, and R is H or OH.
2. The method for preparing the photochromic spiropyran derivative containing an adamantyl group as described in claim 1, characterized in that, The preparation method includes the following steps: 2-(3',3'-dimethyl-6-nitrospiro[chromene-2,2'-dihydroindole]-1'-yl)ethanol, adamantane carboxylic acid compounds, and 4-dimethylaminopyridine were dissolved in an organic solvent, cooled to -5 to 5°C, and dicyclohexylcarbodiimide solution was slowly added dropwise under inert gas protection. The reaction was stirred for 1 to 1.5 h, then heated to room temperature and stirred for another 40 to 46 h. After post-treatment, a photochromic spiropyran derivative containing an adamantane group was obtained.
3. The preparation method according to claim 2, characterized in that, The adamantane carboxylic acid compound is one of 1-adamantanecarboxylic acid, 1-adamantaneacetic acid, and 3-hydroxy-1-adamantaneacetic acid.
4. The preparation method according to claim 2 or 3, characterized in that, The molar ratio of the 2-(3',3'-dimethyl-6-nitrospiro[chromene-2,2'-dihydroindole]-1'-yl)ethanol to the adamantane carboxylic acid compound is 1:
1.
5. The preparation method according to claim 2 or 3, characterized in that, The molar ratio of the adamantane carboxylic acid compound, 4-dimethylaminopyridine, and dicyclohexylcarbodiimide is 1:0.1~0.12:1~1.
1.
6. The preparation method according to claim 2 or 3, characterized in that, The organic solvent is dichloromethane; the dicyclohexylcarbodiimide solution is obtained by dissolving dicyclohexylcarbodiimide in dichloromethane.
7. The preparation method according to claim 2 or 3, characterized in that, The concentration of the adamantane carboxylic acid compound in the organic solvent is 0.02~0.05M.
8. The preparation method according to claim 2 or 3, characterized in that, The post-processing method is as follows: the reaction solution is concentrated under reduced pressure, and then purified by column chromatography using a mixed solvent of petroleum ether and ethyl acetate as the eluent. The collected product is then concentrated and dried.
9. The preparation method according to claim 8, characterized in that, The volume ratio of petroleum ether to ethyl acetate is 3~5:
1.
10. The application of the photochromic spiropyran derivative containing an adamantyl group as described in claim 1 as a solid photochromic material.